In the magnetic recording field, there has been a continuing development effort toward producing magnetic transducer heads of higher and higher resolution. As the effective length measured across the transducing gap of the head is reduced, with a consequent reduction in gap reluctance, higher input signals to the head are generally required to produce a given level of recorded magnetization. The requirement for the use of a superimposed high frequency bias signal can result in undue heating of the head, particularly as the coercivity of the record medium is increased for the sake of higher resolution. The undue heating is a problem in recording heads as well as erasing heads, not only because of possible damage to the record medium, but also because the record medium coating material may be softened and accumulate on the head if the head is operated at relatively high temperatures and slow scanning speeds. Also the magnetic properties of the head core and of the record medium may be adversely affected.
While magnetic records can be monitored shortly after being made, such monitoring has typically been for the purpose of verifying that fact of a recording being made without the availability of immediate correction of the record in the event of an inaccuracy in the recorded signal.